Automated precision machining in tool making

Manufacturing automation strengthens competitive ability 

C. J. van Heerikhuize, Group Managing Director at the central location in 6732 BL Harskamp, Netherlands spoke about the challenges that come with full-service system business: "Our experience has shown that larger units are difficult to control in the business. Because of this we rely on decentralised units, which are more manageable both for individual specialised processes and for the corresponding manufacturing equipment. Each of our three plants, spread over three locations here in the Netherlands, has its own mechanical production and assembly and is also directed independently. The interdisciplinary work we do here allows for parallel manufacturing, mounting and commissioning of tool and handling systems, which significantly reduces our runtimes." In practice, however, this also means that manufacturing capacity has to be reserved in each plant in the form of specialised personnel and machines, which must be flexibly available for use at any time. High output capability is just as much in demand as maximum availability, and those are already two of the reasons why all companies in the Group use CNC machining centres from German manufacturer Maschinenfabrik Berthold Hermle AG, D-78559 Gosheim. A total of 14 Hermle machining centres of various sizes and fitted differently (4 and 5 axes) are currently in use in the four plants. Johan van Veenschoten, Director responsible for mechanical manufacturing, added: "Until 2006, we produced with CNC machining centres. Then we also started using 5-axis technology with Hermle. That worked so well with support from Hermle-Nederland Service and from the main office that within just six months we had arrived at spindle runtimes of 140 hours per week per machine. We have done very well so far with our strategy of preparing NC programmes with Office programming and accompanying simulation to the point where we only have to press the button in manufacturing, so to speak. This is clearly evident for example in the manufacturing of die cast tool systems, where we use six Hermle machining centres and achieve spindle runtimes of over 600 hours per week - and that is with highly flexible and mostly priority-controlled single part and small series production of complex tool components made of tool steels fully hardened to 52 HRC."

 

5-axis milling combined with automatic workpiece management

Because the Brink Group occupies a very special position in the market as a specialist for the die cast tools and turnkey solutions mentioned above, but must also ward off global competition, they are continually searching for additional ways to optimise production, and they have found just that in more extensive manufacturing automation. This is evident for example in the latest investment in parts manufacturing using a 5-axis high-performance machining centre type C 42 UP from Hermle. A combination of the longest possible spindle runtimes and automated 5-axis/5-sided/complete/simultaneous machining plus automated workpiece handling promises not only advantages in productivity, but also shorter throughput times. The C 42 UP was also equipped with the 5X pallet changer type PW 850 for this reason. The 5-axis machining centre also has an additional tool magazine size ZM 160. Together with the basic tool magazine that includes 42 pockets, more than 200 tools are now available for machining the most complex workpieces. As mentioned earlier, depending on packaging volume, the company often manufactures multiple and multi-stage tool systems with corresponding dimensions for basic and component dimensions. With a large working area of X = 800 x Y = 800 x Z = 500 mm compared to the compact C 42 UP machine, the C 42 UP 5-axis high-performance machining centre is ideally equipped for complete machining of tool parts, even larger and heavier ones. The NC-swivelling rotary table, 800 x 630 mm in diameter, provides the required flexibility for 5-axis machining. And because machining includes drilling and face, shoulder or cavity milling in workpiece steels fully hardened to 52 HRC, the high-torque main spindle, which rotates at max. 18,000 rpm, has an HSK-A 63 tool holding fixture and can be fitted with precision drilling and milling tools appropriate for the performance level.

 

Summary

Johan van Veenschoten notes in conclusion: "With the new Hermle manufacturing system, consisting of a C 42 UP 5-axis machining centre and 5x pallet changer, we have another productivity package to use that will definitely save us money. Especially with the help of Hermle's automated machining centres, we have been able to continually and significantly lower manufacturing costs for a long period of eight years, thereby protecting our competitiveness. Not only the machines and pallet changing systems played a large part in this, but also Hermle's excellent customer service, which can be on site quickly and is absolutely competent. When we have a problem, we need help quickly and the service itself should not become a problem, which was the case with previous machine suppliers... . We offer a unit number guarantee of 3 million for our own tools, and we also expect the best services and guarantees from our suppliers. Because we have machining runtimes of one to eight hours for tool parts, some of which are very complex and correspondingly expensive, we have to depend on maximum technical availability and absolute long-term accuracy of the machining. We are on the safe side with Hermle's exemplary performance, reliability and service, and we save even more money."